If you want to work in an international company, it might not be necessary to speak German. But as soon as you are dealing with customers, German is a must.
Our university offers a jobportal, where student jobs and internships are advertised: https://www.stellenwerk-bonn-rhein-sieg.de/en 
Additionally, there are also others:
Jobbörse  of the unemployemnet agency
Some German companies advertise jobs on private portals; however, most are in German.
The ESG (Evangelical Study Community) supports international students, who want to do an internship in their home country. If you get accepted, they'll pay for the flight (max. 1280 EUR) an give you at least 300 to 500 EUR as reimbursement.
- stube.de  (German)
Most international organisations in Bonn offer unpaid internships; However, short unpaid internship are always helpful in building your professional network and acquiring part time job on the basis of your internship experiences. Many UN organisations follow the same rule. Click here  for more information.
- UN Jobs  (English)
We have a lot of students, who work while they are studying. The University Bonn-Rhein-Sieg and our Department offer part-time jobs for enrolled students.
- Language Schools are always looking for native speakers. In addition you can approach families and individuals interested in learning your native language by posting small advertisements on notice boards normally found in super markets and public places.
- International kindergartens (also known as Kita’s) need native speakers. In Bonn, there are a number of international kitas. For instance the http://kayschool.de  and AWO International Kita Bonn 
Restaurants and, Bar’s and Hotels
- Irish Pubs are always looking for staff
- Working in Fast-Food Restaurants
- Hotels with International reputation such as the Maritim and the Grand Kameha in Bonn always need bilingual staff
The United Nations organisations host several meetings and conferences around the year for instance major Climate Change Conferences always held Germany during May/June and in November/December. They are always looking for paid helpers with fluent UN languages such as English, Spanish, French, Arabic. Organisations such as GIZ and other development organisations also need trainers for coaching German staff recruited for international assignments. These trainers are expected to provide training on intercultural competencies and organizational behaviors.
- UN Jobs